The invention relates to a bulk-peeling apparatus and more particularly to roller-type shrimp-peeling machinery.
Originally introduced because of the high labor costs of peeling small shrimp by hand, shrimp-peeling machines are now widely used by shrimp processors. Roller-type peeling machines, in particular, dominate the bulk shrimp-peeling industry. U.S. Pat. No. 2,778,055, Jan. 22, 1957, and U.S. Pat. No. 2,537,355, Jan. 9, 1951, both to Lapeyre et al., describe the basic structure and principles of operation of roller-type shrimp peelers.
Roller-type peeling machines are constructed of parallel peeling channels formed by lower power rollers flanked slightly higher by channel-forming rollers. The channels decline from an infeed end to an outfeed end. The rollers rotate back and forth to loosen shrimp shells in peeling nips between adjacent peeling rollers and to move the shrimp back and forth across the channels to present different orientations of the shrimp to the peeling nips. A finger frame above the peeling channels includes an array of pressure fingers. The finger frame is raised and lowered in synchrony with the back and forth rotation of the peeling rollers. When lowered, the fingers push the shrimp into the peeling nips. When raised, the fingers allow the shrimp to advance along the declining peeling channels. The finger frame is raised and lowered by cams on the peeler frame at the corners of the finger frame. The cams are tilted back and forth. Cam followers attached to the finger frame ride on the reciprocating cams. The conventional cam followers 110, as shown in FIG. 8, consist of a holder 112 with a pair of ears 114 forming a stanchion at a bottom end of the holder. A roller 116 is mounted 118 between the two ears 114 on a hollow bolt. The bolt 118 is supported in aligned holes 120 through the ears 114. The roller 116 has a relatively thin hardened steel outer shell 122 rotationally attached to a ball-bearing hub 124. The hub is stationarily affixed to the bolt 118 so that it does not rotate. The outer shell 122 rotates on the bearing 124. A nut 126 and washers 127 are used to affix the bolt 118 to the ears 114. A lubricant fitting 128 permits lubricant to be added to the bearing 124 through the hollow bolt 118 and an opening 130 in its shaft.
One of the problems with the cam follower shown in FIG. 8 is that the roller 116 is susceptible to cracking, especially when the finger frame, which is hinged to allow it to be tilted up for servicing, is dropped back into position after servicing. The hard, thin outer shell 122 transmits impacts to the ball bearings. The impacts can deform the balls, the bearing race, and the outer shell. Once the bearing starts to fail, the roller starts to slide along the cam rather than roll along it. The sliding wears a groove in the cam, which affects the position of the finger frame relative to the peeling rollers. Often, the roller shell 122 cracks. In both situations peeling performance is compromised, and replacement of the cam rollers and, sometimes, the cams as well, is required.